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Illumination intensity dependence of the recombination mechanism in mixed perovskite solar cells

Illumination intensity dependence of the recombination mechanism in mixed perovskite solar cells
Illumination intensity dependence of the recombination mechanism in mixed perovskite solar cells
Recombination mechanisms in solar cells are frequently assessed through the determination of ideality factors. In this work we report an abrupt change of the value of the “apparent” ideality factor (nAP) in high-efficiency FA0.71MA0.29PbI2.9Br0.1 based mesoscopic perovskite solar cells as a function of light intensity. This change is manifested as a transition from a regime characterized by nAP ~ 1.8-2.5 at low light intensities (< 10 mW/cm2) to one characterized by nAP ~ 1. This transition is equally observed in the recombination resistance extracted from open-circuit impedance measurements. We use drift-diffusion simulations with explicit consideration of ion migration to determine the origin of this transition. We find that a change or recombination mechanism concurrent with a modification of the concentration of ionic vacancies is the most likely explanation of the observed behaviour. In the drift-diffusion simulations we show that the apparent ideality factor is in fact affected by the ion vacancy concentration so it is not the optimal parameter to assess the dominant recombination mechanism. We argue that a procedure based on a recently derived “electronic” ideality factor obtained from the high frequency feature of the impedance spectrum is better suited to determine the recombination route that dictates the photovoltage
mixed perovskite solar cells, diode ideality factor, recombination mechanism, impedance spectroscopy, ionic-electronic coupling
Castro-Chong, Alejandra
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Riquelme, Antonio
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Aernouts, Tom
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Bennett, Laurence, John
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Richardson, Giles
3fd8e08f-e615-42bb-a1ff-3346c5847b91
Oksam, Gerko
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Anta, Juan
85d75dbb-4029-4d9e-b1ad-295a9cdc06bd
Castro-Chong, Alejandra
7bb613ad-273e-469f-96bb-87a6080e9f9f
Riquelme, Antonio
5a5cf964-4ab0-4a12-9c0b-9c0225ed2e58
Aernouts, Tom
2e1e7eb7-57b2-46e3-874f-350c21d71872
Bennett, Laurence, John
47f7f665-ea9f-45fb-a4d6-aad39b6fbff4
Richardson, Giles
3fd8e08f-e615-42bb-a1ff-3346c5847b91
Oksam, Gerko
1921b6df-7496-476c-9c3e-a1f829950f42
Anta, Juan
85d75dbb-4029-4d9e-b1ad-295a9cdc06bd

Castro-Chong, Alejandra, Riquelme, Antonio, Aernouts, Tom, Bennett, Laurence, John, Richardson, Giles, Oksam, Gerko and Anta, Juan (2021) Illumination intensity dependence of the recombination mechanism in mixed perovskite solar cells. ChemPlusChem. (In Press)

Record type: Article

Abstract

Recombination mechanisms in solar cells are frequently assessed through the determination of ideality factors. In this work we report an abrupt change of the value of the “apparent” ideality factor (nAP) in high-efficiency FA0.71MA0.29PbI2.9Br0.1 based mesoscopic perovskite solar cells as a function of light intensity. This change is manifested as a transition from a regime characterized by nAP ~ 1.8-2.5 at low light intensities (< 10 mW/cm2) to one characterized by nAP ~ 1. This transition is equally observed in the recombination resistance extracted from open-circuit impedance measurements. We use drift-diffusion simulations with explicit consideration of ion migration to determine the origin of this transition. We find that a change or recombination mechanism concurrent with a modification of the concentration of ionic vacancies is the most likely explanation of the observed behaviour. In the drift-diffusion simulations we show that the apparent ideality factor is in fact affected by the ion vacancy concentration so it is not the optimal parameter to assess the dominant recombination mechanism. We argue that a procedure based on a recently derived “electronic” ideality factor obtained from the high frequency feature of the impedance spectrum is better suited to determine the recombination route that dictates the photovoltage

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Accepted/In Press date: 3 August 2021
Keywords: mixed perovskite solar cells, diode ideality factor, recombination mechanism, impedance spectroscopy, ionic-electronic coupling

Identifiers

Local EPrints ID: 450755
URI: http://eprints.soton.ac.uk/id/eprint/450755
PURE UUID: d00be223-597e-464d-908a-1fa71d214cbe
ORCID for Laurence, John Bennett: ORCID iD orcid.org/0000-0002-0152-1401

Catalogue record

Date deposited: 10 Aug 2021 16:30
Last modified: 11 Aug 2021 01:49

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Contributors

Author: Alejandra Castro-Chong
Author: Antonio Riquelme
Author: Tom Aernouts
Author: Laurence, John Bennett ORCID iD
Author: Gerko Oksam
Author: Juan Anta

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